1. Field of the Invention
The present invention relates to apparatus and an associated method for resisting carpal tunnel syndrome through reduction of median nerve compression in the carpal tunnel.
2. Description of the Prior Art
According to the United States Bureau of Labor Statistics, carpal tunnel syndrome is the number one cause of occupational cumulative trauma injury in the United States. It is also the fastest growing cumulative trauma injury with over 200,000 new cases reported each year in the United States. According to the National Institute of Safety and Health, carpal tunnel syndrome costs are about at $3,000 per case in employee benefits and up to $40,000 per case in direct medical costs. The median job time lost from a case of carpal tunnel syndrome is 20 days according to the Bureau of Labor Statistics.
Numerous strategies have been proposed to treat or prevent carpal tunnel syndrome. Prevention efforts have consisted of modification of work, home, or avocational activities (Ergonomics). Currently, the most widely accepted non-surgical treatments include wrist splinting, non-steroidal anti-inflammatory medication and local steroid injection. The use of ice, massage, acupuncture and electromodalities have also been employed. When conservative treatment is not effective, surgical division of the transverse carpal ligament is typically recommended. Although statistics are not available, the success rate of conservative treatment is not perceived to be great. Surgical treatment is not always effective and can lead to post-surgical problems, such as reflex sympathetic dystrophy.
Examples of known specific devices that have been designed to prevent or treat carpal tunnel syndrome are various gloves, padding, splints and bandages. Davini U.S. Pat. No. 4,966,137 discloses a splint system consisting of rigid and elastic components applied circumferentially around the wrist. In theory, the device exerts a force to move the radius and ulna closer to each other and, therefore, reduce tension in the transverse carpal ligament to reduce compression of the median nerve.
Downes U.S. Pat. No. 5,413,553 describes a carpal tunnel mitt that is worn like a glove and through a strapping arrangement attempts to approximate the medial and lateral ends of the transverse carpal ligament and thereby reduce tension in the ligament and decompress the median nerve. It is questionable whether either of these devices can overcome the connective tissue forces to accomplish decompression.
Nirsch U.S. Pat. No. 4,441,490, Sebastian et al. U.S. Pat. No. 4,899,763, Nelson U.S. Pat. No. 4,584,993 and Meanchen et al. U.S. Pat. No. 5,014,689 all disclose splints that by various means immobilize the wrist. Maintaining the wrist in a neutral position and restricting movement is thought to minimize pressure in the carpal canal. This type of immobilization has not met with a high success rate and has the further disadvantage of limiting the user's mobility for work or other activities.
U.S. Pat. No. 5,031,640 discloses a pad for preventing carpal tunnel syndrome. This device consists of a padded surface that is interposed between a tool and the user's hand. While this device may lessen point pressure over the median nerve during tool use, it does not represent a device that can provide long term relief of carpal tunnel syndrome.
Fareed U.S. Pat. No. 5,441,058 discloses a device designed to provide circumferential pressure in the forearm area. This device could not be employed to effect dorsally directed force to the flexor tendons in the palm area.
Stoner U.S. Pat. No. 5,478,306 discloses a system for supporting carpals through providing circumferential pressure in the carpal area.
Sucher U.S. Pat. No. 5,468,220 discloses a device for applying a stretching force to the medial and lateral ends of the transverse carpal ligament. See also Sucher U.S. Pat. No. 5,256,136 which discloses stretching the transverse carpal ligament through positioning of the hand and thumb in an abducted position.
My co-pending U.S. patent application Ser. No. 08/826,778 discloses a device for stretching the intrinsic hand muscles and is generally adapted to be used during rest periods.
There remains, therefore, a very real and substantial need for an improved system for reducing median nerve compression in the carpal tunnel through applying a dorsally directed force in the palm region.